As a rule controlling a complex electrical grid requires a suitable control and protection system which stabilizes the electrical grid, particularly in critical or unforeseen situations. Such a control and protection system is often also known as a CPS (Control and Protection System). A CPS is used as a control system for normal operating conditions of the electrical grid and also as a protection system for abnormal or critical operating conditions.
Especially in complex electrical grids with a large number of grid components, oscillations which span the grid components frequently occur in important operating parameters such as the current, voltage, output, load flow and/or phase. Such oscillations are often referred to as power oscillations (PO). They occur, for example, when a large power generator, such as a wind farm, is separated from the electrical grid. In such cases the loss of power caused thereby has to be compensated through other generators of the electrical grid producing additional power. The transition of power generation from the wind farm to one or more compensating generators generally exhibits a very complex dynamic transitional behavior, wherein the complexity is due to a plurality of grid-component-internal control loops of the involved grid components. In particular, the transition can lead to considerable oscillations between different generators which can result in failure of the electrical grid if suitable countermeasures are not taken in time.
Frequently used to dampen such oscillations are so-called power system stabilizers which are coupled to synchronous generators of conventional power stations. The power system stabilizers are often also known as PSS. In addition, other damping devices, such as PODs (Power Oscillations Dampers) are also used to damp oscillations in the case of HVDC stations. In general PSS and PODs are manually configured for a pre-determined set of test scenarios. In an operating range of the electrical grid covered by such test scenarios, acceptable oscillation damping can usually be achieved in this way. However, as soon as an unforeseen operating status or one not covered by the test scenarios suddenly occurs during the operation of the electrical grid, the damping efficiency can be considerably reduced and a critical situation can thereby arise.